Artificial hand



D. w. DORRANCE ARTIFICIAL HAND Filed Feb. 5, 1926 2 Shets-Sheet 1 Pig. I.

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' D. W. DORRANCE ARTIFICIAL HAND Filed Feb. 5, 1926 2 Sheets-Sheet 2 I I {s3 in a gmemto'o Patented Dec. 18, 1928 entree STATES FATE a? OFFICE.)

ARTIFICIAL HAND.

Application filed February My invention relates to improvements in artificial hands of the type including a pivoted thumb, an object of the invention being to supply simple, durable and effective means for actuating said thumb.

A further objectof the invention resides in providing such thumb actuating means, wherein but'little of the mechanism is ex- 'posed to vicw and whereby a follow-up grip of the thumb is effected.

7 Another object of the invention is to supply a thumb actuating means, as above, the

same being adapted constantly to resist opening swinging movement of the thumb by extraneous forces.

With the foregoing and other objects i.- view, which will appear in the foil description, the. invention resides in novel combination and arrangement of pads and in the details of cons ruction hereinafter described and claimed.

In the drawings, F 1 is a side view of an artificial hand embodying my invention, the detachable side plate being removed to disclose the interior mechanism which otherwise would be concealed. F 2 is a. View similar to Fig. l, the thumb 'being illustrated as swung back out of the normal position shown in l and the associated parts shown in the relation assumed thereby in such position of said thumb; F 3 and i are transverse sectional views respectively taken on the lines 33 aud tl of F 1, and Fig. 5 is a perspective view in detail of the traveler which is reciprocably disposed within the handpropen.

Reference being had to the draw ngs, it will be observed that the illustrated embodiment of my invention includes a structure closely simulating the human hand, said structure including a metacarpus or main hand portion 10, fingers 11- and a thumb 12.

- Preferably, the main hand portion 10 and fingers 11 are built up andfcarved out of a light, strong wood. The thumb 12 is formed independently of said parts 10 and 11 of thehand, said thumb being pivoted to the hand proper by means of a pin 13,21

portion 14 of said thumb on which a cam surface 15 is formed, finding room to swing in a recess 16 cut into the main hand portion 10 and opening laterally at the front thereof. A second recess 17 also opening at the front of the hand is formed in said hand portion 10 and joining said recesses 16and 17 is a way 18 extending longitudinally of the 5, 1926. serm No. 86,214.

hand. Thumb actuating parts, presently to be described, are housed within the recesses 16 and 17 and way 18, all being normally! covered by means of a side plate 10 constituting a part of the hand proper, and r movably secured in place by screws 19 threaded into the body of the. main hand portion 10. Reciprooably slidable in the way 18 is a traveler 20 (Fig. 5.) which has a head 21 providinga cam 22, said headbeing notched to. provide a spring seat '23. Opposite the head 21, the traveler body 20 is notched, as at 24, to form an abutment 25. The head 21 of said traveler 2O occupies positions within the recess 16, while the:

abutment25 occupies positions within the recess 17. interposed between the wall 26 of the .recessllG and the seat 28 in the traveler 20 is a coiled expansion spring 27, which yieldingly operates to push the traveler 20 been in the way 18. Such backward movement of said traveler 20 is attended with a closing swinging movement of the thumb 12 due to the form of the cam 22-and the said cam coacts. In this connection it is follow-up grip of the thumb against an object tending to become free from the'hold of said thumb. Further, it will be noted that any tendency of the thumb to open, as by an external force, will be effectively resisted by the follower 20, due to the design of the cam 22 and cam surface 15, whereby any pressure of the latter against the cam 22 results mainly in pressing, the follower 20 against the wall 28 of the recess 16. A lever 29 playing in the recess 17,-is pivoted medially to the main hand portion 10 on c a screw 30 applied thereto. The inner end said thumb and the first fingers 11 or against said fingers (Fig. 1) in the absence of such object. It will also be understood that a pull upon the cord 33 will swing the lever in a direction to thrust the traveler 20' for- 'cam surface 15 on the thumb with which ward against 'the action ofthe spring 27.

all)

tically no resistance against the openi During such movement of said traveler 20, the thumb 12 is allowed to swing open and to so swing said thumb, it provide a link the same being pivoted one end on a screw in the lever 29 and at other end on a screw 36 in the thumb portion i l, s link, plays in a groove in the inne of the side plate 10 andmay be relatively light as its sole function is to SWll the thumb 12 open as it is permitted so swing by the forwardly moving traveler 20 And it is, of course, understood that there is prac- 0f pared with the Vt ance encountered st the closing thereof and met by th relatively strong structure incluoing the pressed traveler 20 -At the end OI the main hand portion 10, opposite the fingers 11, is a t ireaded stud 38 for application to usual aim-stump socket. l s ith this stud screwed, into such socket and the cord 33 appropriately pallet and slackened, my improven'ient rovi less an effective substitute for the lldli n hand that is sightly in appearance and e o i Changes in the specific fo tion, herein disclosed, may be made wt the scope of what is claimed without departing from the spirit of my invention.

l-laving described my invention, what claim cw and desire to PIOtCCJlJY Let ters Patent is:

1. An artificial hand including a main portion provided with fingers and with a thumb pivoted thereon and formed with a cam surface, a traveler reciprocably mount ed within said main portion and formed with a cam thereon adapted to co-act with the thumb 12 as co said cam surface to resist opening swinging movement of said thumb by extraneous force, also to impart closing swinging movement to the thumb upon movement of the traveler in one direction, an expansion spring operating against said traveler to move the same in that direction, and an actuating lever pivoted on said main portion, one end of said lever cooperating with saiu traveler to shift the same against the action. of said spring and thereby free the traveler from the thumb;

2. An artificial hand including a main por ion provided with fingers and with a thumb pivoted thereon and formed with a cam surface, a traveler reciprocably mounted within said main portion and formed movementof said thumb by extraneous force, also to impart closing swinging movement to the thumb upon movement of the traveler in one direction, an expansion spring operating against said traveler to move the same in that direction, and an actuatinglever pivoted on said main portion', one end of said lever cooperating with said traveler to shift the same against the action of said spring and thereby free the travel r from the thui'nb, and a link joining said lever with said thumb for imparting pening swinging movement to ;the latter;

3. An artificial hand including a main "ion provided with fingers and with a thumb pivoted thereon and formed with a cam surface, a traveler movably mounted l main portion and formed with a cam thereon adapted to coact with said can"; surface to resist opening swinging ement of said thumb by; extraneous fOltQ, also to impart closing 'swingingmovemont to the thumb upon movement of the traveler in one direction, means for moving said traveler in that direction, other means for moving the traveler in the opposite direction to free the thumb, and additional )ortion Jrovided .with fin ers and with a 1 thumb pivoted thereon and formediwith a cam surface, a traveler reciprocaloly mounted within said main portion and formed with-a cam surface thereon adapted to coact with said first cam surface to resist substantially uniformly the opening swin ing movement of the thumb by extraneous force in the various relative positions of said cam surfaces, also to swing the-thumb toward the fingers upon movement of the traveler in one direction, means for moving the t aveler in that direction, and independent means for oppositely moving said traveler.

in testimony whereof, name to this specification.

DAVID W. DORRANCE.

l have signed my 1 

